Apparatus for automatically cutting defective veneer sheets



A. s. HAMMOND 3,165,961

APPARATUS FOR AUTOMATICALLY CUTTING DEFECTIVE VENEER SHEETS 2 Sheets-Sheet 1 INVENTOR BERT s. HAMMOND (QM Q W ATTORNEYS Jan. 19, 1965 Filed Nov. 30, 1962 w m m o N\ Q no .u Q\ M. .Q

Jan. 19, 1965 A. s. HAMMOND 3,165,961

APPARATUS FOR AUTOMATICALLY CUTTING DEFECTIVE VENEER SHEETS- Filed Nov. 30, 1962 Sheets-Sheet 2 INVENTOR.

ALBERT s. HAMMOND A TTOANE YS United States Patent 3,165,961 APPARATUS FOR AUTGMATICALLY CUTTTNG DEFECTIVE VENEER SHEETS Albert S. Hammond, North Bend, Wash, assignor to Weyerhaeuser Company, Tacoma, Wash, a corporation of Washington Filed Nov. 30, 1962, Ser. No. 241,223 7 Claims. (til. 83365) This invention relates to apparatus for automatically cutting defective veneer sheets in half to produce crossbanding for plywood. Specifically, this invention relates to apparatus for automatically cutting defective veneer sheets in half by using photoelectric tubes that detect the defective portions in the veneer sheet and automatically actuate a saw to cut the veneer sheet in half.

In the art of peeling veneer sheets for plywood, open defects in portions of the green veneer sheets often render half of an 8-foot sheet useless. These defective veneer sheets are pulled from the green chain and cut in half to produce cross-banding veneer sheets. This is time consuming and requires that the operator examine each piece of veneer sheet and judge the size of open defects. In the past, many efforts have been made to reduce the labor required for this operation. However, all systems used the judgment of an operator to grade the size of open defects.

There are many disadvantages inherent in the above operation. For example, since the veneer sheets move rapidly along the production line, theoperator examining the veneer sheets may overlook many open defects in s the veneer sheets. Moreover, when the operator spots an open defect in the traveling veneer sheet, he must then clip the veneer sheet and remove the clipped veneer sheet from the production line.

It isa principal object of the present invention to provide apparatus for eliminating the errors in visually grading defects in a traveling veneer sheet.

It is another object of this invention to provide apparatus for automatically grading open'defects in veneer sheets and automatically cut the defective portion of the veneer sheet in half.

It is another objectof this invention to provide apparatus for grading defectsin veneer sheets by a photoelectric tube system.

These and other objects will become clear to those skilled in the art When taken in conjunction with the present detailed description and drawings wherein:

FIGURE 1 is a side elevational view, partly in section, of the automatic veneer saw and clipper table embodying the present invention.

FIGURE 2 is a top plan view of the automatic veneer saw and clipper illustrated in FIGURE 1.

FIGURE 3 is a cross-sectional view taken on line 3-3 of FIGURE 1.

FIGURE 4 is a cross-sectional view similar to FIG- URE 3 but illustrating a veneer sheet having a permissible open defect.

Referring to the drawings, an automatic veneer saw unit is generally indicated at 1 and is suitably supported by a carriage 5 above a clipper table 2 having the usual belts 3 for moving the veneer sheets 4- towards the clipper generally indicated at 19.

A motor 6 is mounted on the carriage 5 for driving the saw unit 1. The motor 6 is provided with the usual pulley 9 for driving a sprocket 7 by the belts 8 interconnecting the pulleys on the sprocket and pulley member 9. The sprocket member 7 is carried by and rotates on a shaft member 18. Pivotally connected to the shaft 18 is a support member 12 which carries a saw shaft 11. Belts 10 are suitably connected between pulleys on the shaft 11 and pulleys on the sprocket 7 so that the rotative apart.

amass]. Fatented Jan. 19, 1965 "Ice force of the motor 6 will rotate the sprocket member 7 and also shaft member 11. Rigidly connected to the shaft member 11 is a saw blade 17 which as shown is mounted between two guard members 13.

Suitably mounted on a pivot pin 16 on support member12 is an air cylinder 14 connected to a suitable source of air pressure, not shown. The upper end of the cylinder 14 is pivotally connected to the carriage by a pivot pin 15.

A first bank of light source 21 is mounted underneath the table 2 on a shaft or rod 20. The light source 21 extends transversely across the path of the veneer sheet 4. As shown in FIGURE 3, the light source 21 comprises a plurality of lights spaced a predetermined distance Directly above the light source 21, a bank of photoelectric tubes 23 are mounted on asuitable shaft or rod 22. The photoelectric tubes 23 are spaced a predetermined distance apart.

Spaced downstream of and directly under the saw blade 17 is mounted a second bank of light source 25 suitably mounted on a rod or shaft 24 beneath the table 2. The bank of light source'25 extends transversely entirely across the path of the veneer sheets 4. Directly above the light source 25 and above the table 2 is mounted a second bank of photoelectric tubes 27 suitably mounted on a shaft or rod 26. The bank of photoelectric tubes 23 and 27 also extend transversely entirely across the path or" the veneer sheet 4.

The photoelectric tubes 23 and 27 are of any conventional design that generate electricity to excite a circuit when a light source is beamed thereon;

The first photoelectric bank 23 is designed to actuate the saw member 17 to lower it into a cutting position when a defective portion in the veneer sheet travels underneath or between the source of light 21 and tubes 23. This is accomplished by connecting the photoelectric tubes 23 to a suitable valve mechanism to operate an air source, notshown, which in turn actuates cylinder member 14/ The photoelectric tubes 23 are spaced apart a sufficient distance that it requires a beam of light to focus on at least two of the tubes 23 in order to actuate the cylinder member 14 to lower the saw 17.

The second bank of photoelectric tubes 27 and light source 25 are suitably connected to the same valve, not 5 shown, to elevate the saw unit when the defective portion in the venmr sheet 4 interrupts the light beam shining between the source 25 and the tubes 27.

The electrical circuit for use with the photoelectric tubes 27 and 23 may be of any conventional design and may be connected thereto in a manner well-known in the art.

In operation, the operator first determines the permissible size of open defects in the veneer sheets 4. Then the photoelectric tubes 23 are set a predetermined distance apart and a predetermined distance above the table 2.

The veneer sheets 4 are then placed on the table 2 and moved toward the clipper 19 by the belts 3. When an open defect occurs in the veneer sheet 4, such as shown at 28 in FIGURE 3, a light beam 30 from the source 21 will extend through the defective opening 28 and focus on at least two photoelectric tubes 23. The current generated in the tubes 23 will excite a valve and allow air pressure to act on the cylinder 14 to lower the saw. Since the saw 17 is located equidistant from the edges of the veneer sheet 4, it will cut the veneer sheet 4 in half for a distance determined by the greatest opening of the defect as it moves along the table 2. It should be noted that the saw 17 will remain in the lowered cutting position until the open defect 28 has passed the saw blade 17.

As the open detect 2% moves along the table 2, an-

other light beam will extend therethrough from the light source and focus on the photoelectric tubes 27. The circuit is arranged in such a manner that this expedient will not raise the saw. However, when the training edge of the open defect 28 cuts off the beam of light between the source 25 and photoelectric tubes 27, the air pressure in cylinder 14 is relieved and the saw is raised. In this manner a centerline cut is made on the veneer sheet the length of which will be at least equal to the greatest open path of the defect in the direction of travel of the veneer. Actually, the length of the said centerline cut will be slightly longer than the said open path of the defect since the saw blade 17 is 50' positioned with respect to the saw lowering 23 and saw raising 27 photoelectric tubes that it is slightly ahead of the former and slightly behind the latter.

The defective portion of the veneer sheet 4 that has been cut in half moves along the table 2 and is clipped by the clipper 19 and removed for producing stock for cross-banding.

Referring to FIGURE 4, a veneer sheet 4' is shown having an open defect 29. However, the opening 29 is of a permissible size and the light beam 30 will focus on only one photoelectric tube 23. Therefore, the saw 17 will not be lowered to cut the veneer sheet 4' in half since the beam 30 must focus on at least two photoelectric tubes 23 to lower the saw 17.

In place of the single center cut saw shown in the illustrative modification, several saws may be positioned across the width of the veneer so that when the sensing eyes indicate detects the appropriate saws would drop to produce one piece of cross-banding from the center of the sheet.

While specific details of a preferred embodiment have been set forth above, it will be apparent that many changes and modifications may be made therein without departing from the spirit of the invention. It will therefore be understood that what has been described herein is intended to be illustrative only, and is not intended to limit the scope of the invention.

What is claimed is:

1. An apparatus for cutting defective portions of veneer sheets, comprising: a clipper table adapted to convey veneer sheets to a clipper mechanism; a veneer saw mounted above said clipper table including a saw adapted to be lowered and raised; and means for detecting open defective portions in the veneer sheets and adapted to lower the saw to cut the defective portion of the veneer sheet in half.

2. Anyapparatus for cutting defective portions of veneer sheets, comprising: a clipper table adapted to convey veneer sheets to a clipper mechanism; a veneer saw mounted above said clipper table including a saw 4 adapted to be lowered and raised; means for detecting open defective portions in the veneer sheets and adapted to lower the saw to cut the defective portion of the veneer sheet in half, and means to raise the saw after the defective portion of said veneer sheet has been cut.

3. An apparatus for cutting defective portions of veneer sheets, comprising: a clipper table adapted to convey veneer sheets to a clipper mechanism; a veneer saw mounted above said clipper table including a saw and a means to raise and lower said saw; and means for detecting open defective portions in the veneer sheets and adapted to actuate said saw lowering means to cut the defective portion of the veneer sheet in half.

4. An apparatus for cutting defective portions of veneer sheets as set forth in claim 2 wherein: said means for detecting open defective portions in the veneer sheet includes a bank of light source below said clipper table and a bani: of photoelectric tubes above the table.

5. An apparatus for cutting defective portions of veneer sheets as set forth in claim 2 wherein: said means for raising said saw includes a bank of light source and a bank of photoelectric tubes.

6. An apparatus for cutting defective portions of veneer sheets comprising: a clipper table adapted to convey veneer sheets to a clipper mechanism; a veneer saw mounted above said clipper table including a saw and means to raise and lower said saw; means for detecting open defective portions in the veneer sheets includin a bank of light source below said clipper table and a bank of photoelectric tubes above said clipper table; and means to raise said saw including another bank of light source and another bank of photoelectric tubes above said table.

7. An apparatus for cutting defective portions in veneer sheets as set forth in claim 6. wherein said open defective portion must be of a width to allow a beam of light from said light source to focus on at least two photoelectric tubes to lower said saw.

References Cited in the file of this patent UNITED STATES PATENTS Switzerland June 15, 1957 

1. AN APPARATUS FOR CUTTING DEFECTIVE PORTIONS OF VENEER SHEETS, COMPRISING: A CLIPPER TABLE ADAPTED TO CONVEY VENEER SHEETS TO A CLIPPER MECHANISM; A VENEER SAW MOUNTED ABOVE SAID CLIPPER TABLE INCLUDING A SAW ADAPTED TO BE LOWERED AND RAISED; AND MEANS FOR DETECTING OPEN DEFECTIVE PORTIONS IN THE VENEER SHEETS AND ADAPTED TO LOWER THE SAW TO CUT THE DEFLECTIVE PORTION OF THE VENEER SHEET IN HALF. 